If you ever find yourself in a situation where you need to cook but there is no electricity or access to a portable charcoal or gas stove, then you might want to consider making a portable stove with an aluminum can and a pocket knife.

A beer-can stove, or soda-can stove, is a homemade, ultralight portable stove. The simple design is usually made entirely from aluminum cans and burns alcohol. Countless variations on the basic design exist.

Of the available fuels, methanol delivers the least energy, ethanol somewhat more, butanol is hardly ever used, and isopropanol delivers the most. All but isopropanol burn with a smokeless flame; it can provide both light and heat.

Boil times can be significantly reduced by using a pot of the appropriate diameter (to reduce heat loss up the side of the pot) and wind screens which maximize efficiency.
Time to boil 2 cups (500 ml): ~5 minutes at 6500 ft (2000m) altitude with ambient temp of ~45F (7C) and water temp of ~55F (13C).

Most of the items needed to make this stove can be found in most homes.

Denatured alcohol is a (relatively) environmentally-friendly fuel that does not leave a residue or soot. Denatured alcohol is commonly available at camping outfitters and hardware stores. Denatured alcohol is toxic to drink.

Non-toxic pure ethanol is rarely used as stove fuel in the United States, since it is usually subject to a liquor tax. However oftentimes the cost of pure ethanol is worth carrying on hikes as it has some medicinal use including treating stings and bites, as a coolant, and antiseptic. Pure ethanol also has a recreational application in flamed desserts such as fruits flambe, despite expense.

These stoves operate marginally on 90% isopropyl alcohol, poorly on 70% and not at all with 50%. Water typically cannot be boiled with isopropyl rubbing alcohol, but if the more rarely found (still inexpensive) laboratory grade or “gas drier” is used, and the sooting is dealt with by applying a little soap solution to the pot, the fuel value of the alcohol will reduce boiling times, not increase them.